Calendar / Performance Series - Session #2

Environmental Conditions & Context

Identify the environmental, site, and contextual conditions that define the stresses a house must manage, anchoring decisions in actual exposure rather than generic best practice.

How this fits in the series

Builds on: P1 (desired performance outcomes)
Leads to: P3 (loads on buildings & occupants), P4 (failure mechanisms & modes)

Core concepts and execution implications

  • Conditions define the problem space.
    • Can identify key climate/site stressors for the local context.
  • Climate averages aren't enough; exposure matters.
    • Can include site/drainage/wind/solar/smoke context in decisions.
  • Strategies must be condition-specific.
    • Can avoid one-size-fits-all assemblies and explain context fit.

Connections

Stressors to consider

Water exposure
  • Rain + wind-driven rain: how often, from which direction, and how hard
  • Snow/ice: drifting, ice dams risk, melt-refreeze cycles
  • Ground water + surface drainage: slope, downspout discharge, splashback
Temperature + sun
  • Cold + big daily swings: expansion/contraction and condensation risk at weak points
  • Solar exposure: overheating, UV degradation, south/west orientation penalties
  • Dry air: shrinkage/cracking, occupant comfort, material movement
Wind + airborne
  • Wind: pressure loads, infiltration drivers, embers and debris in events
  • Dust/smoke: filtration and intake placement implications (details later)

Explore in PF: Climate (B1), Weather (B2), Water/Hydrology (B3), Air Quality (B5)

Where things go wrong

These failures aren't "mysteries." They're usually the predictable result of a missed stressor: water, wind, sun, temperature swing, or site drainage. Common patterns include leak paths at edges (roof transitions, wall-to-foundation, decks, penetrations), wind-driven rain wetting behind cladding, ice damming and meltwater backup, and sun-driven UV/heat degradation. Examples:

  1. "The windy wall"
    Moderate rain + strong wind → repeated wetting through small defects → staining, rot, callbacks.
    Root issue: wind exposure underestimated
    Field check: inspect wind-exposed walls for flashing continuity and drainage gap before cladding closes
  2. "Good roof, bad edge"
    Roof field performs, but a transition (valley/skylight/chimney) leaks season after season.
    Root issue: edge conditions ignored
    Field check: walk every roof transition and verify flashing lap direction before roofing covers it
  3. "Drainage didn't matter… until it did"
    Downspouts and grading look fine on day one → long-term splashback and wet foundation zone.
    Root issue: site water management
    Field check: verify grade slopes away from foundation and downspout discharge clears splash zone

Explore in PF: Water/Hydrology (B3), Geological/Seismic (B4)

Reflection: Which single environmental stressor causes the most callbacks or complaints in your local area?

Curated resources

Top resources from our curated library mapped to this session's topics.

References & resources